The invention relates to a circuit arrangement with a piezoelectric transformer having two electrodes arranged on the primary side of the transformer and such a piezoelectric transformer itself.
Piezoelectric transformers are known electrical components which utilize the direct piezoelectric effect and simultaneously its reversal in a component. Electrical energy is first transformed into mechanical energy on the primary side and this mechanical energy is again transformed into electrical energy after internal transmission of mechanical energy from the primary to the secondary side. A piezoelectric transformer is predominantly used as a voltage transformer which transforms a low voltage (AC voltage) applied to the primary-side electrodes into a high voltage (AC voltage) which may be tapped from the output electrodes on the secondary side. A circuit arrangement including such a piezoelectric transformer for controlling an LCD is known, for example, from the publication by M. Sugimoto et al.; SID 96, Digest, p. 757 (1996).
Since a piezoelectric transformer is to be operated with an AC voltage on the primary side, control electronics are provided in known circuit arrangements which control electronics first transform an available DC voltage into an AC voltage which is then applied to the primary side of the piezoelectric transformer. These control electronics, however, require relatively much space compared with the small space required by the piezoelectric transformer, especially because of its lower height (compared with conventional inductive transformers).